A method of a high stability selectable hydrogenate catalyst producing and using for DMCHD manufacturing
The present invention relates to a method of a high stability selectable hydrogenate catalyst producing and using for DMCHD manufacturing. When Dimethyl tetephthalate(DMT) with the selectable hydrogenate catalyst produced Dimethyl 1,4-cyclohexanedicarboxylate (DMCHD), said catalyst do not lost activate over 500 hours and maintain DMCHD production ratio over 90% in a long time. This develop of research about manufacture of DMCHD, relate to industry, could reduce most cost of production and elevate efficiency of economy.
In U.S. Pat. No. 5,399,742 and U.S. Pat. No. 5,319,129 suggests that cyclohexanedimethanol (CHDM) used to produce condensation polymer and particular monomer of polyester in currently, more particularity, used to produce the poly 1,4-cycohighhexanedimethylene terephthalate (PCT), there is high performance and high incident value, and glycol modified PET(PETG). However, the dimethyl 1,4-cyclohexanedicarboxylate(DMCHD) is one of the intermediate products during the reaction when made CHDM, first we must synthetic DMCHD for production of CHDM. So there is very high value of economy to DMCHD, the way of industry commit the development of research.
So far, catalyst to synthetic DMCHD has two catalysts system one is Pdxe2x80x94Al2O3 the other is Ru/Al2O3. When used catalyst of Pd/Al2O3, it need more high pressure (10-200 bar) and more high temperature (140-400xc2x0 C.). It is easy to infect by CO of sub-production. Although the more novelty catalyst of Ru/Al2O3 can react in more low pressure (10-175 bar) and more low temperatures 150-230xc2x0 C.), without a matter of infection by CO of sub-production, and the fault of said catalyst so easy lost activation that employ too short about prescription and low production. The mainly reason of fault used mismanaged in activation condition so that too large particle of catalyst and distribution irregularity.
Table 7 gives conventional Ru/Al2O3 catalyst activation and reaction life, the conditions are pressure 700-750 psig, temperature 120xc2x0 C., DMT ""s space velocity 24 hourxe2x88x921. It is no obviously shifting but maintain high effectively 95%, DMT conversion  DMCHD selectivity and DMCHD yield capacity, in reaction 5.3 hours. After 5.3 hours, DMT conversion  DMCHD selectivity and DMCHD yield capacity is a large range decrease. After 240.1 hours, DMT conversion is 21.1%, DMCHD yield capacity is 16.47%, it is no tally for useful of industry and efficiency of economy. The DMCHD industry wanted to overcome that the fault of conventional Ru/Al2O3 catalyst is easier loss of activation.
It is an object of the present invention to produce high stability for selectable hydrogenate catalyst having a catalyst to maintain long-term activation.
It is another object of the present invention to produce high stability for selectable hydrogenate catalyst having a activation method to produce a catalyst which used in synthetic DMCHD, the synthetic reaction process is in lower temperature and lower pressure. Thus, the catalyst is not easy loss activation and have long life of reaction, and maintain excellent stability and activation after long-term reaction. The industry is not reduce cost but also increase yield capacity, it is good for industry and relation industry.
It is another object of the present invention to produce high stability for selectable hydrogenate catalyst having a excellent reaction condition, convenient temperature  pressure  velocity of hydrogen gas  space velocity of DMT material and concentration of DMT solution, react with said catalyst of selectable hydrogen reaction that could get 99% DMCHD yield capacity.